Timing refers to where the ports line up. With breaks like the muscle break, large ports point out to the side and the brake needs to be timed so they line up in the right place. On other brakes that have holes all the way around, they don't need to be timed and can go on however.

YES radial, ie blast goes everywhere,I have one.Lot of the newer are directional, usally both side and some with top porting also. Break intended to be horizontal to shooting plane, if that type was off 1/4, to vertical position then it would blow stuff all over you if prone in the dirt like speed goat hunting.